Both seconded!

I also quite like Tom Aikens and Pied a Terre. They are probably a little cheaper than Le Gavroche and Alain Ducasse at the Dorchester, and a bit more casual. Some people find Le Gavroche a bit stuffy but I like it that way.

By the way, I would consider none of those places to be kids friendly, unless the kids are exceptionally well-behaved, i.e. no loud noises, no running around, know how to eat neatly and use the cutlery properly etc etc.

Lunch time is good for getting value for money. Evening meals at all the places above are not what most people would call 'cheap' although they are, to me, worth the money.